Information on allergic rhinitis (AR) and asthma (A) was obtained from a sample of the US population aged 6 years to 24 years in the second National Health and Nutrition Examination Survey 1976-1980 (NHANES II). Analyses were limited to 4,877 whites. Eighty-six percent had complete data. Catarrhal symptoms related to both season and pollen were labeled AR and wheezing was labeled A. The overall prevalent of AR was: 6-12: 6.2%; 12-17: 7%; 18-24: 9%. The overall prevalence of A was: 6-12: 6.2%; 12-17: 3.9%; 18-24: 4.5%. A peaked in the age range 6-12 and AR peaked in the age range 17-24. Eight, 1:20 wt/vol, 50% glycerol, unstandardized extracts were administered by prick puncture. Allergen reactivity was reported as the percent with a mean erythema diameter 10.5 mm or greater at 20 minutes. Only the prevalence of asthma and allergic rhinitis increased with the increasing number for positive allergen skin tests. The independent association of individual allergen reactivity with respiratory disease was quantified with logistic models that included other allergen reactivity, age, sex, smoking and region. Asthma was associated with reactivity to house dust (odds ratio, 2.9; 95% confidence interval [CI] 1.7 to 5) and Alternaria (odds ratio 5.1; 95% CI: 2.9 to 8.9). Allergic rhinitis was associated with reactivity to ragweed (odds ratio, 2.3; 95% CI: 1.5 to 3.3); ryegrass (odds ratio, 2.8; 95% CI: 1.8 to 4.3); house dust (odds ratio, 2.5; 95% CI 1.6 to 3.9); Alternaria (odds ratio, 2.3; 95% CI: 1.5 to 3.4). Asthma only (without allergic rhinitis) was associated with dust and Alternaria. Allergic rhinitis only (without asthma) was associated with ryegrass, ragweed, and house dust. When both A and AR were present only house dust and Alternaria remained associated. These findings highlight the association of specific allergens with upper and lower respiratory diseases and the interactions among coexisting respiratory disease.